Photographic material for the silver dye bleach process



United States Patent Int. Cl. G03c1/10, /52

US. Cl. 96--99 9 Claims ABSTRACT OF THE DISCLOSURE The invention relates to photographic materials for the silver dye bleach process, which materials contain certain di-(naphthyl-azo)benzene cyan dyes fast to light and with particularly suitable spectral properties.

Dyes for the known silver dye bleach process have to meet very high requirements. These dyes must be spectrally suitable, the absence of absorption in unwanted spectral regions next to the position of the absorption maximum being of particular significance. In addition, they must be able to be bleached rapidly and completely. The bleaching of cyan dyes should not pass through red monoazo intermediate stages which may cause the formation of a disturbing red fog. The dyes must be resistant to diffusion in the binder used, which, in practically all cases is gelatin, and it must as far as possible be inert to the photographic emulsion. In addition, it should be fast to light.

A large number of cyan dyes have already been described but they are of limited utility, since they do not meet the requirements referred to hereinbefore.

It is among the objects of the present invention to provide cyan azo dyes which are suitable for the silver dye bleach process. A further object is to provide light-sensitive silver halide emulsion layers, which contain such cyan azo dyes.

We now have found that dyes of the following formula are excellently suitable for the silver dye bleach process:

OR, OR, OH NHR4 X SOaH 503K wherein:

R =alkyl, hydroxyalkyl or alkoxyalkyl;

R =alkyl, alkoxyalkyl, hydroxyalkyl or hydroxyalkyl that is esterified with an aliphatic carboxylic acid containing preferably up to 5 carbon atoms, more particular with a dicarboxylic acid containing up to 5 carbon atoms;

R =hydrogen, alkyl, alkoxy, hydroxy substituted alkoxy,

hydroxy substituted alkoxy when the hydroxy is esterified with an aliphatic carboxylic acid containing preferably up to 5 carbon atoms, more particular with a dicarboxylic acid containing up to 5 carbon atoms, alkoxyalkyl or alkoxyalkoxy;

R =acyl, preferably acyl which is derived from aliphatic or aromatic carboxylic acids, in particular benzoyl and substituted benzoyl, suitable substituents being, for example, halogen such as chlorine or bromine, alkyl radicals or halogenated alkyl radicals such as CF amino groups, alkyl or phenyl-substituted amino, acyl substituted amino, the acyl group of which being preferably derived from an aliphatic carboxylic acid having up to 5 carbon atoms, more particular from a dicarboxylic acid containing preferably up to 5 carbon atoms, or alkoxy groups;

X=hydrogen or SO H; the SO H-groups are preferably in the 3- and 6-position.

The alkyl-, hydroxyalkyl-, alkoxyalkylor alkoxyalkoxy groups mentioned above preferably contain up to 3 carbon atoms per alkyl group.

Dyes of the above formula in which R is an alkoxyor alkoxyalkoxy group are particularly useful.

Suitable dyes include those of the following formulae:

SOaH

0on1, 002115 on Nn-o ol N=N -N:N 4) F 002115 110 3 SO3H 00:11:; OCzH-1OC2H5 ()H NH-CQ 0021140 C2H5 HOaS -SO3H The preparation of the dyes according to the invention may, for example, be carried out as follows:

1-amino-2-ethoxynaphthalene-7-sulfonic acid (A) is diazotized indirectly and coupled to a 1-amino-2,5-dialkoxy-or 1-amino-2,5-dialkoxy-alkoxybenzene (B). The amino azo dye obtained is again diazotized indirectly and again coupled, this time to a l-acylamino-S-hydroxynaphthalene-3,6-disulfonic acid (C), e.g., 1-(3'-trifiuoromethyl benzoyl) amino 8 hydroxynaphthalene 3, -disulfonic acid.

The following compounds are suitable for use as diazo components A:

1-amino-2-methoxynaphthalene-7-sulfonic acid, 1-amino-2-[3-ethoxy-ethoxynaphthalene-7-sulfonic acid, 1-amino-2-hydroxyethoxynaphthalene-7-sulfonic acid, 1-amino-2 methoxynaphthalene-6-sulfonic acid.

The following are examples of compounds which may be used as coupling components B:

1-amino-2-me thoxy-S-methylbenzene, 1-amino-2-methoxybenzene, l-amino-Z,S-dimethoxybenzene, l-amino-2,S-dihydroxyethoxybenzene, 1-amino-2,S-diethoxybenzene,

1-amino-2,5- (diglutaroylhydroxy-ethoxy -benzene, 1-amino-2-hydroXyethoXy-benzene, 1amino-Z-ethoxyethoXybenzene, 1-amino-2-hydroXy-ethoXy-5-methylbenzene, and 1-amino-2-ethoxyethoxy-S-methylbenzene.

The following compounds may, inter alia, be used as coupling components C:

1-(3-trifluoromethylbenzoyl)-amino-8-hydroxynaphthalene-4-sulfonic acid.

The dye of Formula 6 can, for example, be prepared as follows:

26.7 parts by weight of 1-amino-2-ethoxynaphthalene- 7-sulfonic acid are dissolved in 300 parts by volume of a dilute aqueous solution of sodium carbonate and diazotized indirectly according to common practice. A hydrochloric acid solution of 15.3 parts by weight of 1-arnino-2,5-dimethoxybenzene in 300 parts by volume of water is then added. Coupling is effected at pH 3.5 by the addition of sodium acetate solution (20%). After coupling is completed, the reaction solution is adjusted to pH 1 with concentrated hydrochloric acid, and the amino monoazo dye precipitated is isolated at 70 C. The dye obtained is dissolved at pH 8.5 and diazotized indirectly in known manner. The diazotized monoazo dye partly precipitates. After completion of the diazotization the dye is added to a solution of 45.2 parts by weight of 1 (3 glutaroylaminobenzoyl) amino 8 hydroxynaphthalene-3,6-disulfonic acid, 20 parts by weight of sodium carbonate, parts by volume of pyridine and 300 parts by volume of water. The resulting green tinted dye is salted out.

With the high diffusion resistance of the dyes according to the invention, the adjustment between solubility of the dye in water and its diffusion resistance in the layer can be varied as best suited to the particular working conditions mainly by varying the different substituents R in the manner indicated. Therefore, by a suitable combination of substituents, the new dyes do not require any mordanting with organic bases such as aromatic dibiguanides or the like.

The particular working conditions depend mainly on the desired acid strength of the dye bleaching bath and the associated degree of hardening of the layers. This possibility constitutes a further advantage over known dyes of a similar type.

Another advantage lies in the high degree of purity in which the compounds according to the invention are obtained by the method of preparation indicated, so that time-consuming purification by reprecipitation is not necessary. Owing to their good spectral properties, their high fastness to light and the ease with which they can be bleached, combined with their low tendency to the formation of the red monoazo form in the case of only partial bleaching with low color densities, the dyes according to the invention are eminently suitable for all modification of the silver dye bleach process, e.g., a combination of the silver salt diffusion process and the silver dye bleach process suitable for the production of colored images with a characteristic curve opposite to that of the original, as well as for processes which comprise a black-white reversal development. As dye bleaching baths either thiourea baths can be used such as mentioned in British Patents Nos. 397,159 and 507,211 and described, e.g., in German Auslegeschrift 1,041,355 or baths containing quinoline and iodide as indicated in US. Patents Nos. 2,629,658 and 2,652,328. Another advantage of the dyes of the present invention lies in the longer wavelength absorption and the more advantageous form of the Slopes of the absorption curves compared with cyan dyes known in the art. In this connection, it should be specially pointed out that in the field of azo dyes, the preparation of dyes suitable for the silver dye bleach process with an absorption maximum above 600 nm. in gelatin is particularly diflicult if at the same time the undesired absorption in the blue spectral region (400 to 500 nm.) must be kept low. The short-wave absorption slope (towards the green region of the spectrum (500-600 nm.) is in this case of decisive importance, especially for a clear and pure reproduction of green, because the human eye is particularly sensitive in this region.

The superiority of the dyes according to the invention precisely in this respect compared with the most closely related known dyes is readily apparent from the comparison tests given in the table below. This table shows the absorption maxima and the degree of absorption of the dyes for the specified shorter wavelengths. The smaller the degree of absorption at these shorter wavelengths the more advantageous are the dyes. The figures are based on measurements carried out on 0.2% gelatin solutions of these dyes and the degree of absorption at the lower wavelengths is given as a relative value based on an optical density of the absorption maximum of 1.00:

8 sitized with gold salts as described by R. Koslowsky, Z.wiss.phot. 46 (1951), 6272.

The emulsions employed can also be chemically sensitized with reducing agents, such as stannous salts, polyamines, sulfur compounds, such as described in US. Patent No. 1,574,944, polyethylene oxides and the like.

The emulsions may also contain stabilizers such as organic mercury compounds, heterocyclic compounds, in particular mercapto substituted heterocyclic rings, such as triazoles, tetrazoles or azaindenes, which are disclosed, e.g., by Birr in Z.wiss.phot., vol. 47 (1952), pages 2-28.

The emulsions can also be optically sensitized with sensitizing dyes customarily employed in the art of emulsion making, such as cyanines, merocyanines as described, e.g., by F. M. Hamer The Cyanine Dyes and related Compounds published by Interscience Publishers (1964).

It is preferred to use sensitizinug dyestuffs from the merocyanine class, such as described, e.g., in Belgian Patent No. 659,657 and sulfo betaine cyanines.

The emulsion may also be hardened by any suitable hardener such as formaldehyde, halogen substituted aliphatic acids such as mucobromid acid and the like. In view of the treatment with the strongly acidic dye-bleaching bath, very active hardeners are preferred.

The emulsions may contain a suitable gelatin plasticizer such as ethylene glycol, other dihydroxy alkanes, pentaerythritol phosphoric acid esters as described in German Patent No. 1,185,811 and the like.

Relative degree of absorption at shorter wavelengths, in 11111.

Absorption Dyestufi maximum 520 540 560 570 580 590 600 Standard dye 003 0.16 0. 24 0.45 0. 035 0.80 0.02 0.90 2 005 0.41 0.570 0.73 0.87 0.985 3 012 13 0.175 0.30 0.42 0.55 0.72 0.00

As a standard dye and dye of the following formula was Example 1 used: 300 ml. of a 3% gelatin solution containing 2.0 g. of OH OCH: OH 40 dye No. 13 and 0.4 g. of saponin are added to 500 ml. of a silver bromide gelatin emulsion containing about mol percent of silver iodide. The emulsion is sensitized to red light with 12 mg. of the sensitizer according to 0011, 503E Example 11 of German Patent No. 1,213,240 and poured The dyes according to the invention can be used equally successfully for single layered and multi-layered materials for the silver dye bleach process as explained in the following examples.

The azo dyes of the present invention are added to a light-sensitive silver halide emulsion layer. The concentration of the dyes can be varied depending upon the concentration of the silver halide and the effects desired. In general we have found that g. per mol of silver halide are sufficient for the purpose of our invention.

As binding agent for the silver halide emulsion layer the hydrophilic colloids can be used which are custom arily employed for dispersing silver halides, for example, gelatin, alone or in combination with other proteins such as albumin, alginic acids and derivatives thereof such as alkali salts, polyvinyl alcohol, polyvinyl pyrrolidones, carboxylalkyl cellulose such as carboxymethyl cellulose etc.

The photographic emulsions may be coated on any of the customary supports for photographic material including paper, cellulose esters, such as cellulose acetate or nitrate, polystyrene, polyesters, in particular polyethylene terephthalate, polycarbonates, preferably bis-hydroxy phenyl alkanes, and the like.

The emulsions may be chemically sensitized by any of the accepted procedures. The emulsion can be treated with salts of noble metals such as ruthenium, rhodium, palladium, iridium or platinum. Suitable compounds are well known in the art. The emulsions can also be senover a support of baryta-coated paper or cellulose triacetate. The silver application is about 0.8 g. Ag/m. After drying, the film is exposed to yellow light under a stepped grey wedge and processed as follows:

(1) Development 5 minutes in a solution of:

1 g. of p-methylaminophenol 13 g. of Na SO sicc. 3 g. of hydroquinone 26 g. of soda sicc. and 1 g. of potassium bromide in 1000 ml. of water (2) Washing for 1 minute. (3) Fixing 5 minutes in a solution of:

200 g. of sodium thiosulfate cryst. 20 g. of potassium metabisulfite in 1000 ml. of water (4) Washing for 5 minutes. (5) Hardening for 5 minutes in a solution of 60 ml. of

formalin (30%).

5 g. of sodium bicarbonate in 1000 ml. of water (6) Washing for 5 minutes. (7) Dye bleaching for 15 minutes in a solution of:

10 g. of potassium iodide 10 g. of sodium hypophosphite 25 ml. of sulfuric acid 50 ml. of quinoline 10 mg. of 2,3-dimethylquinoxaline in 1000 ml. of

water (8) Washing for 5 minutes. (9) Bleaching 5 minutes in a bath of:

25 g. of copper chloride 9 10 ml. of hydrochloric acid cone. in 1000 ml. of water The layers indicated below are arranged successively Fixing 10 minutes as under 2. on a support of baryta-coated paper:

(11) Washing for minutes.

After drying, a cyan dye wedge is obtained which has perfect whites which do not stain or get dissolved even 5 after rolon ed ex osure to li ht. The low color densities of the wedg are v Z ithout any reddish tinge and are very g fizg 3 3 33: z' g ggi fi iigi gg gg f j fast to hght' iodide content of 3 mol%, 15 mg. of a sensitizer de- Example 2 scribed in Example 2 of German Patent No. 1,213,240

The procedure is the same as indicated in Example 1 10 and 2.5 g. of the dye of the following formula:

(1) A red sensitized layer as indicated in Example 1, (2) an intermediate layer applied from a 2% gelatin solution,

\/ SOaH SOaH HOzS- 2 but the dye is replaced by 2.0 g. of dye No. 14 and the dissolved in 250 ml. of a 2% gelatin solution which emulsion is applied onto a white pigmented cellulose trialso contains the usual quantities of hardening agents acetate foil. After exposure, and processing in baths 1 (e.g. 4 ml. of a 30% aqueous formaldehyde solution) to 6 as in Example 1, the procedure is as follows: and 0.4 g. of saponin. The silver concentration is 0.8

(4) an intermediate layer applied from a 2% aqueous gelatin solution,

(5) a yellow filter layer (optical density 0.5 for a layer thickness of 1 mm.) obtained from a 2% gelatin (7) 5 minutes dye bleaching in a solution of:

28 g. of thiourea 18 g. of potassium bromide 3 mg. of 2-amino-3-hydroxyphenazine 400 ml. of hydrochloric acid cone. in 1000 ml. of

Water solution, (8) Washin for 5 minutes (6) an intermediate layer applied from a 2% gelatin g solution,

(9) Bleach fixing 10 minutes in a solution of:

26 g. of tetrasodium-ethylenediamine-tetraacetate 24 g. of soda sicc. 15 g. of iron (III) chloride 13 g. of sodium sulfite sicc. 3

200 g. of sodium thiosulfate sicc. in 800 ml. of

water. 00 NH--O 0-NH-N=N (10) Washing for 20 minutes.

(7) a non-sensitized silver halide gelatin emulsion layer 35 containing 25 g. of silver bromide per kg. and per 500 g. 5 g. of a yellow dye of the following formula:

| NH The result obtained is quite similar to that in Example 1. Both layers are eminently suitable as cyan dye sloaH layer in a color photographic three-layer material. ((EHZ);

CODE 2 Example 3 in addition to the usual quantities of hardening agents (4 ml. of a 30% aqueous formaldehyde solution) and 0.5 g. of saponin. The silver concentration is about 0.7

The procedure is as described in Example 1 with the exception that the dye is replaced by approximately the same quantities of one of the dyes Nos. 5 or 7 to 9. After ex osure and rocessin as in Exam le 1, similar results obtained. p g p (8) a protective layer apphed from a 2.5% aqueous gela- Example 4 tin solution.

Processing The procedure is as described in Example 2 but after exposure it is processed as follows: After drying, the film is exposed behind a multi-colored transparency and processed as described in Example 1, Development for 5 mlflutes 111 a bath as lndlcated 111 with the exception that 50 mg. of 2,3-dimethylquinoxaline Example 1. are added to the bleaching bath and the treatment time (2) Washing for 1 minute. is increased to 20 minutes. 31630111115 for mlnu'te In a SolutlOIl of: After washing with water and drying, a reproduction in 10 of P a smm :bichromate true colors of the original is obtained. The resulting color 5 f Sulfllflc ac ld COHC- In 300 Of Waterphotographic image has an unusual brilliancy. (4) Washing for 1 mlnute. We claim: Treatment for 1 mlnute n a bath of 5 f sodlum 1. Light-sensitive photographic material with at least Sulfit 81c ln 1 f Watefone light-sensitive silver halide emulsion layer dyed with E gvsashlng f r 1 ng-11 h 40 an azo dye of the following formula:

. minutes secon exposure wit a w. lncan- 5 descent lamp at 20 cm. distance. (IJRl i R T (8) Second development as under 1. (9) Hardening and further processing as in Example 1 with baths 5-11. 1, A cyan dye wedge is obtained which has a characteristic X SOSH curve opposite that of the original. 803E Example 5 wherein: A color photographic multi-layer material for the silver- R represents alkyl, hydroxyalkyl or alkoxyalkyl;

dye-bleach process is prepared as follows: R represents alkyl, hydroxyalkyl, hydroxyalkyl esteri- 3,467, 522 11 12 fied with aliphatic carboxylic acid or alkoxy alkyl; sensitive silver halide emulsion layer dyed with an azo R represents hydrogen, alkyl, alkoxy, hydroxy substidye of the following formula:

tuted alkoxy, hydroxy substituted alkoxy, the hydroxy R1 0R2 OH NHRl group of which is esterified with an aliphatic carl boxylic acid, alkoxyalkyl or alkoxyalk-oxy; R represents the acyl group of a carboxylic acid; and X represents hydrogen or sulfo. R3

2. Light-sensitive material as defined in claim 1, where- X in R represents a benzoyl group.

3. Light-sensitive material as defined in claim 1, wherewherein in the azo dye has the following formula: R represents alkyl, hydroxy substituted alkyl or alkoxy 803K 4. Light-sensitive material as defined in claim 1, wheresubstituted alkyl, the alkyl groups of which have up in the azo dye has the following formula: to 3 carbon atoms;

R represents alkyl, having up to 3 carbon atoms, hy-

droxy substituted alkyl having up to 3 carbon atoms, hydroxy substituted alkyl having up to 3 carbon atoms and the hydroxy group of which is esterified 00511 OH with an aliphatic carboxylic acid having up to 5 car- I bon atoms or alkoxy substituted alkyl, the alkoxy group of which has up to 3 carbon atoms;

l R represents hydrogen, alkyl having up to 3 carbon :11 803K atoms, alkoxy having up to 3 carbon atoms, hydroxy substituted alkoxy having up to 3 carbon atoms, hy-

droxy substituted alkoxy having up to 3 carbon atoms and the hydroxyl group of which is esterified with 35 an aliphatic carboxylic acid having up to 5 carbon 5. Light-sensitive material as defined in claim 1, whereatoms or alkoxy substituted alkoxy, the alkyl groups in the azo dye has the following formula: of which have up to 3 carbon atoms;

00,11, 101120111011 H NHO o-Q N=N N=N CH, (ECHzCHzOH SOJiH S0311 $0311 6. Light-sensitive material as defined in claim 1, where- R represents an acyl radical derived from an aliphatic in the azo dye has the following formula: carboxylic acid having up to 3 carbon atoms or a OCzHa ocmcmocmcm m NHOC-QCI S0311 7. Light-sensitive material as defined in claim 1, wherebenzoyl radical; and in the azo dye has the following formula: X represents hydrogen or sulfo.

0,115 001134002115 (|)H NH-C O-Q OCzH4OCzH5 $0 K $03K S0311 8. Light-sensitive material as defined in claim 1, where- References Cited in the azo dye has the fOllOWiIlg formula: UNITED STATES PATENTS 0 ,11, 0011, 0 NHHQ 2,286,838 6/1942 Seymour et a1. 96-99 2,629,658 2/ 1953 Sprung 96-99 7 3,157,508 11/1964 Dreyfuss 9699 S0311 S0311 I. TRAVIS BROWN, Primary Examiner H US. Cl. X.R. 96-20, 53, 73

9. A light-sensitive material with at least one light- 75 

